Differences in Free Amino Acids Between Stocks of the Same Long‐Time Inbred Line of Maize ( Zea mays L.) 1

Qualitative analysis was made for free amino acids by two‐dimensional descending paper chromatography in four stocks of long‐time corn inbred CI 7 ( Zea mays L.). We detected eight amino acids in 60 lambdas of the North Carolina and Arkansas sources, whereas only four were found in the stocks from Athens and Beltsville. However, seven amino acids were detected in 100 lambdas of the Athens and Beltsville stocks. Apparently, the North Carolina and Arkansas stocks differ quantitatively, rather than qualitatively, from the Athens and Beltsville stocks with respect to the free amino acids—asparagine, glutamine, glycine, and probably arginine. These findings are in agreement with a previous report by us on variations between these stocks for seedling and quantitative biochemical characters. Stocks within supposedly homozygous lines may differ in the number and/or amount of amino acids present in the seedlings. Thus biochemical analyses may become more useful as techniques in the identification and isolation of genotypes in breeding programs and in basic genetic and cytogenetic studies. These variations may be due either to mutation or residual heterozygosis , or to both. The possibility of episomal systems or regulatory genes as a part of mutation or residual heterozygosis should not be overlooked.